Polyurethanes containing sulphide groups, polymeric mixtures based thereon, production and use thereof

ABSTRACT

Novel polyurethanes containing sulfide groups which comprise at least one group of the general formula I in the polymer main chain and/or at least one group of the general formula II incorporated at the chain end: 
     —X—A—S—B—Y—  (I) 
     —X—A—S—B—YH  (II) 
     in which the variables have the following definitions:  
     S is the sulfur atom;  
     X and Y independently of one another are oxygen atoms, sulfur atoms or groups —NZ where Z is the hydrogen atom or an alkyl radical of 1 to 10 carbon atoms; and  
     A and B independently of one another are divalent organic radicals;  
     novel polymer mixtures based thereon, and the use of the novel polyurethanes and polymer mixtures and dispersions thereof for the preparation of coating materials, adhesives and sealing compounds.

[0001] The present invention relates to novel polyurethanes containingsulfide groups and to novel polymer mixtures based thereon. The presentinvention further relates to the preparation of the novel polyurethanescontaining sulfide groups and of the polymer mixtures based thereon. Thepresent invention further relates to novel dispersions which comprisethe novel polyurethanes containing sulfide groups and/or the novelpolymer mixtures based thereon. The present invention additionallyrelates to the use of the novel polyurethanes containing sulfide groups,of the polymer mixtures based thereon, and of their dispersions toprepare novel coating materials, adhesives and sealing compounds.Furthermore, the present invention relates to the preparation of novelcoatings, adhesives and seals on and in primed and unprimed substrates.Not least, the present invention relates to the primed and unprimedsubstrates coated with a novel coating, bonded with a novel adhesivefilm and/or sealed with a novel seal.

[0002] In the context of the present invention, polymer mixtures areunderstood as polymeric materials which result from the polymerizationof olefinically unsaturated monomers in the presence of polyurethanes.They may comprise graft copolymers, containing very small amounts, ifany, of polyurethanes and (co)polymers of the olefinically unsaturatedmonomers. Alternatively, the polymer mixtures may comprise thepolyurethanes and the (co)polymers. Moreover, the mixtures may comprisegraft copolymers, polyurethanes and (co)polymers of the olefinicallyunsaturated monomers.

[0003] Polymer mixtures based on polyurethane are known. They arenormally prepared by polymerizing olefinically unsaturated monomers inthe aqueous dispersion of a hydrophilic or hydrophobic polyurethanecontaining terminal and/or lateral, olefinically unsaturated groups inthe polymer chain. Groups of this kind may be incorporated

[0004] into the polyurethane chain by way of maleic acid or fumaric acidand/or esters thereof,

[0005] by way of compounds containing two isocyanate-reactive groups andat least one olefinically unsaturated group, or by way of compoundscontaining two isocyanate groups and at least one olefinicallyunsaturated group, laterally to the polyurethane chain,

[0006] by way of compounds containing one isocyanate-reactive group andat least one olefinically unsaturated group, or by way of compoundscontaining one isocyanate group and at least one olefinicallyunsaturated group, terminally to the polyurethane chain, or

[0007] by way of anhydrides of alpha,beta-unsaturated carboxylic acids.

[0008] In this respect, reference is made by way of example to thepatent applications and patents DE 197 22 862 C2, DE 196 45 761 A1, EP 0401 565 A1, EP 0 522 420 A1, EP 0 522 419 A2, EP 0 755 946 A1, EP 0 608021 A1, EP 0 708 788 A1 or EP 0 730 613 A1 and to the German patentapplications DE 199 53 446.2, DE 199 53 445.2 or DE 199 53 203.6,unpublished at the priority date of the present specification.

[0009] In the context of the present invention, the property of beinghydrophilic is understood as the constitutional property of a moleculeor functional group to penetrate into the aqueous phase or to remaintherein. Accordingly, in the context of the present invention, theproperty of being hydrophobic is understood as the constitutionalproperty of a molecule or functional group to exhibit exophilic behaviorwith respect to water; i.e., such molecules or groups display thetendency not to penetrate into water, or to depart the aqueous phase.For further details, reference is made to Römpp Lexikon Lacke undDruckfarben, Georg Thieme Verlag, Stuttgart, N.Y., 1998,“Hydrophilicity”, “Hydrophobicity”, pages 294 and 295.

[0010] The known polymer mixtures based on polyurethane are used inparticular to prepare aqueous basecoat materials. The known aqueousbasecoat materials serve primarily to produce color and/or effectbasecoats in multicoat systems by the wet-on-wet technique, asdescribed, for example, in the patents and patent applications recitedabove.

[0011] However, the preparation of the known polymer mixtures based onpolyurethane may present problems.

[0012] For instance, lateral and/or terminal allyl groups are frequentlyincorporated as grafting centers. The reactivity of the allyl groups,however, is comparatively low. If the more reactive acrylate ormethacrylate groups are used instead of them, gelling of thepolyurethanes may occur even before or during the graftcopolymerization.

[0013] In many cases, not least, the amount of olefinically unsaturatedgroups in the polyurethanes may prove too low for complete grafting, sothat a large proportion of the monomers intended for grafting on formsseparate homopolymers and/or copolymers alongside the polyurethane,which may adversely affect the performance properties of the polymermixtures and of the coating materials, adhesives and sealing compoundsprepared using them. This disadvantage cannot be eliminated readily byincreasing the double bond content of the polyurethanes for grafting,since to do so is to the detriment of other important performanceproperties of the polyurethanes.

[0014] Polyurethanes containing thiol groups, especially terminal thiolgroups, are known.

[0015] The German patent application DE 40 17 940 A1 disclosesalpha,omega-difunctional prepolymers which contain terminal thiol groupsand which contain thiocarbamate groups in the chain. They are preparedby reacting dithiols with diisocyanates. They can be used to preparelinear polymers, networks, casting resins, composites, laminates,adhesives, coatings, coated materials, and as starting products for thepreparation of thermoplastic materials of high molecular mass. However,no details of these end uses are given.

[0016] The German patent application DE 35 08 428 A1 disclosesoligourethanes containing terminal thiol groups. They are prepared byreacting polyisocyanates with a substoichiometric amount of polyols andmercaptoalkanols. They are used as binders for oxidatively curablecoating materials and sealing compounds, as additives for epoxy resins,or as crosslinking agents for plastics precursors or plastics comprisingolefinically unsaturated compounds.

[0017] The German patent application DE 21 21 478 A1 discloses a processfor crosslinking polymers containing thiol groups. Crosslinking agentsused comprise nitrile N-oxides or precursors thereof such aspoly(hydroxamoyl halides).

[0018] The German patent application DE 34 07 031 A1 discloses a processfor preparing chemically curable or water-vulcanizable adhesives,coating materials, sealing compounds and casting compositions based onpolyurethanes. In this process, prepolymers containing free isocyanategroups are reacted with prepolymers containing thiol groups, which areobtainable by reacting the prepolymers containing free isocyanate groupswith mercaptoalkanols.

[0019] The German patent application DE 20 28 892 A1 discloses a curablecomposition comprising a constituent having two or more olefinically oracetylenically unsaturated bonds and a polythiol as crosslinking agent.The reaction between these constituents may be accelerated by means ofalpha-hydroxy carboxylic acids.

[0020] It is an object of the present invention to provide novel polymermixtures based on polyurethane which no longer have the disadvantages ofthe prior art but which instead can be prepared in high yields, simplyand in a targeted manner, in the presence of readily availablehydrophilic and hydrophobic polyurethanes, and which have very goodperformance properties irrespective of whether they contain large orsmall amounts of homopolymers and/or copolymers. The novel polymermixtures based on polyurethane should be suitable for the preparation ofaqueous coating materials, adhesives and sealing compounds which onand/or in primed and unprimed substrates provide coatings, adhesivefilms and seals whose profile of properties is at least equal if notsuperior to that of existing coatings, adhesive films and seals.

[0021] Accordingly, we have found the novel polyurethane containingsulfide groups which comprises at least one group of the general formulaI in the polymer main chain and/or at least one group of the generalformula II incorporated at the chain end:

—X—A—S—B—Y—  (I)

—X—A—S—B—YH  (II)

[0022] in which the variables have the following definitions:

[0023] S is the sulfur atom;

[0024] X and Y independently of one another are oxygen atoms, sulfuratoms or groups —NZ where Z is the hydrogen atom or an alkyl radical of1 to 10 carbon atoms; and

[0025] A and B independently of one another are divalent organicradicals.

[0026] In the text below, the novel polyurethane containing sulfidegroups is referred to as the “polyurethane of the invention”.

[0027] We have also found the novel polymer mixture based on thepolyurethane of the invention, which is preparable by polymerizing atleast one olefinically unsaturated monomer in a solution or aqueousdispersion of at least one hydrophobic or hydrophilic polyurethane ofthe invention.

[0028] In the text below, the novel polymer mixture is referred to asthe “polymer mixture of the invention”.

[0029] Furthermore, we have found the novel process for preparing thepolyurethane of the invention, in which at least one compound of thegeneral formula III is incorporated into the polymer main chain and/orat the chain end:

HX—A—S—B—YH  (III)

[0030] in which the variables have the following definitions:

[0031] S is the sulfur atom;

[0032] H is hydrogen atoms;

[0033] X and Y independently of one another are oxygen atoms, sulfuratoms or groups —NZ where Z is the hydrogen atom or an alkyl radical of1 to 10 carbon atoms; and

[0034] A and B independently of one another are divalent organicradicals.

[0035] Moreover, we have found the novel process for preparing a polymermixture by polymerizing at least one olefinically unsaturated monomer inthe presence of at least one hydrophilic or hydrophobic polyurethane ofthe invention.

[0036] Additionally, we have found the novel aqueous dispersions of thepolyurethane of the invention and of the polymer mixture of theinvention.

[0037] Furthermore, we have found the novel coating materials, adhesivesand sealing compounds based on the polyurethane of the invention, on thepolymer mixture of the invention and/or on their dispersions.

[0038] Furthermore, we have found the novel coatings, adhesive films andseals on and/or in primed and unprimed substrates, which are referred tobelow as the “coatings, adhesive films and seals of the invention”.

[0039] F Further subject matters of the invention will emerge from thedescription.

[0040] In the light of the prior art it was surprising that the complexobject on which the present invention is based could be elegantlyachieved with the aid of the polyurethanes of the invention and of thepolymer mixtures of the invention. Even more surprising was that nospecial new apparatus or procedural measures were necessary either forthe process for preparing the polyurethanes of the invention or for theprocess for preparing the polymer mixtures of the invention, but thatinstead it was possible to employ the apparatus and procedural measuresknown from the prior art. In this context it should be emphasized thatsaid processes of the invention are not accompanied by the proceduraland safety problems associated with the use of olefinically unsaturatedpolyurethanes, such as the gelling of the mixture, for instance. Afurther surprise was the extremely broad applicability of thepolyurethanes, polymer mixtures and dispersions of the invention.

[0041] The preparation of the polymer mixture of the invention startsfrom at least one, preferably one, hydrophilic or hydrophobicpolyurethane of the invention.

[0042] The polyurethane of the invention contains at least one group ofthe general formula I in the polymer main chain and/or at least onegroup of the general formula II incorporated at the chain end:

—X—A—S—B—Y—  (I)

—X—A—S—B—YH  (II)

[0043] in which the variables have the following definitions:

[0044] S is the sulfur atom;

[0045] X and Y independently of one another are oxygen atoms, sulfuratoms or groups —NZ where Z is the hydrogen atom or an alkyl radical of1 to 10 carbon atoms; and

[0046] A and B independently of one another are divalent organicradicals.

[0047] Examples of suitable alkyl radicals Z are methyl, ethyl, propyl,butyl, pentyl, hexyl, heptyl, octyl, nonyl or decyl.

[0048] The divalent organic radicals A and B may be identical to ordifferent from one another. Suitable radicals A and B are all divalentorganic radicals which are not isocyanate-reactive.

[0049] Examples of suitable divalent organic radicals are substituted orunsubstituted aliphatic, cycloaliphatic, aromatic,aliphatic-cycloaliphatic, aliphati-caromatic and/orcycloaliphatic-aromatic divalent radicals which may contain heteroatomsbut which must not be isocyanate-reactive.

[0050] Suitable substituents are electron-withdrawing orelectron-donating atoms or organic radicals which are notisocyanate-reactive.

[0051] Examples of suitable substituents are halogen atoms, especiallychlorine and fluorine, nitrile groups, nitro groups, partially or fullyhalogenated, especially chlorinated and/or fluorinated, alkyl,cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, aryl, alkylaryl,cycloalkylaryl, arylalkyl and arylcycloalkyl radicals; aryloxy, alkyloxyand cycloalkyloxy radicals, especially phenoxy, naphthoxy, methoxy,ethoxy, propoxy, butyloxy or cyclohexyloxy.

[0052] In accordance with the invention, the unsubstituted divalentorganic radicals A and B which contain no heteroatoms are of advantageand are therefore used with preference in accordance with the invention.

[0053] Especially suitable divalent aliphatic radicals A and B arederived from aliphatic hydrocarbons such as methane, ethane, propane,butane, pentane, hexane, heptane, octane, nonane or decane.

[0054] Especially suitable divalent cycloaliphatic radicals A and B arederived from cycloaliphatic hydrocarbons such as cyclobutane,cyclopentane, cyclohexane, norbornene or decalin.

[0055] Especially suitable divalent aromatic radicals A and B arederived from aromatic hydrocarbons such as benzene, naphthalene orbiphenyl.

[0056] Especially suitable aliphatic-cycloaliphatic divalent radicals Aand B are derived from aliphatic-cycloaliphatic hydrocarbons such asethylcyclopentane or methylcyclohexane.

[0057] Especially suitable aliphatic-aromatic divalent radicals A and Bare derived from aliphatic-aromatic hydrocarbons such as toluene orxylene.

[0058] Especially suitable cycloaliphatic-aromatic divalent radicals Aand B are derived from cycloaliphatic-aromatic hydrocarbons such ascyclohexylbenzene or cyclohexylbiphenyl.

[0059] Very special suitability is possessed by the divalent aliphaticradicals A and B, especially the ethane-1,2-diyl radical (dimethyleneradical).

[0060] Accordingly, the group of the general formula I used with veryparticular preference is the 1,7-dioxa-4-thiaheptane-1,7-diyl group andthe group of the general formula II used with very particular preferenceis the 1,7-dioxa-4-thiaheptan-1-yl group.

[0061] The polyurethanes of the invention preferably contain at leastone, in particular at least two, chain-positioned groups of the generalformula I. In addition, they may also contain at least one, inparticular at least two, terminal groups of the general formula II. Theamount of groups of the general formula I or of groups of the generalformula I and II may be set for the polyurethanes of the invention byway of the stoichiometric proportions of the starting compounds, whichare described below.

[0062] The polyurethanes of the invention are of linear, star-branchedor comblike construction, but especially linear. Apart from the groupsof the general formula I and/or of the general formula II which areessential to the invention, they may contain further functional groups.

[0063] For instance, both the hydrophilic and the hydrophobicpolyurethanes of the invention may contain reactive functional groups bymeans of which the resultant polymer mixtures of the invention becomethermally self-crosslinking or externally crosslinking. A prerequisite,however, is that these reactive functional groups do not disrupt orinhibit the graft copolymerization.

[0064] The hydrophilic polyurethanes generally contain alternatively

[0065] (f1) functional groups which can be converted into cations byneutralizing agents and/or quaternizing agents, or

[0066] (f2) functional groups which can be converted into anions byneutralizing agents, and/or anionic groups, and/or

[0067] (f3) nonionic hydrophilic groups, especially poly-(alkyleneether) groups,

[0068] which promote the dispersibility of the polyurethanes and of thepolymer mixtures of the invention in water.

[0069] Examples of suitable functional groups (f1) for use in accordancewith the invention, which can be converted into cations by neutralizingagents and/or quaternizing agents, are primary, secondary or tertiaryamino groups, secondary sulfide groups or tertiary phosphine groups,especially tertiary amino groups or secondary sulfide groups.

[0070] Examples of suitable cationic groups (f1) to be used inaccordance with the invention are primary, secondary, tertiary orquaternary ammonium groups, tertiary sulfonium groups or quaternaryphosphonium groups, preferably quaternary ammonium groups or tertiarysulfonium groups, but especially tertiary sulfonium groups.

[0071] Examples of suitable functional groups (f2) for use in accordancewith the invention, which can be converted into anions by neutralizingagents, are carboxylic acid, sulfonic acid or phosphonic acid groups,especially carboxylic acid groups.

[0072] Examples of suitable anionic groups (f2) for use in accordancewith the invention are carboxylate, sulfonate or phosphonate groups,especially carboxylate groups.

[0073] Examples of suitable neutralizing agents for functional groups(f1) convertible into cations are organic and inorganic acids such assulfuric acid, hydrochloric acid, phosphoric acid, formic acid, aceticacid, lactic acid, dimethylolpropionic acid or citric acid.

[0074] Examples of suitable neutralizing agents for functional groups(f2) convertible into anions are ammonia or amines, such astrimethylamine, triethylamine, tributylamine, dimethylaniline,diethylaniline, triphenylamine, dimethylethanolamine,diethylethanolamine, methyldiethanolamine, 2-aminomethylpropanol,dimethylisopropylamine, dimethylisopropanolamine or triethanolamine, forexample. Preferred neutralizing agents used are dimethylethanolamineand/or triethylamine.

[0075] Advantageously, depending on the type of stabilization, thepolyurethane of the invention has an acid number or amine number of from10 to 250 mg KOH/g (ionic stabilization or nonionic plus ionicstabilization) or from 0 to 10 mg KOH/g (nonionic stabilization), an OHnumber of from 30 to 350 mg KOH/g and a number average molecular weightof from 1500 to 55,000 daltons.

[0076] The polyurethanes of the invention may be prepared by anydesired, customary and known methods of polyurethane chemistry. Inaccordance with the invention, however, it is of advantage to preparethem by the reaction of an isocyanato-containing polyurethane prepolymerwith at least one compound of the general formula III

HX—A—S—B—YH  (III).

[0077] In the general formula III, the variables have the definitionsstated above for the general formula I and II. Examples of highlysuitable compounds of the general formula III are, accordingly,thiodiethanol, thiodicyclohexan-4-ol or thiodiphenol, but especiallythiodiethanol.

[0078] The isocyanato-containing polyurethane prepolymers compriselinear, star-branched or comblike polymers or oligomers. It is preferredto use linear polyurethane prepolymers.

[0079] In the context of the present invention, here and below,oligomers are resins which contain at least 2 to 15 monomer units intheir molecule. In the context of the present invention, polymers areresins which contain at least 10 monomer units in their molecule. Forfurther details of these terms, reference is made to Römpp Lexikon Lackeund Druckfarben, Georg Thieme Verlag, Stuttgart, N.Y., 1998,“Oligomers”, page 425.

[0080] The reaction of the isocyanato-containing polyurethaneprepolymers with the compounds of the general formula III has no specialfeatures in terms of its method but instead takes place in accordancewith the customary and known methods of the chemistry of organicpolyisocyanates, as are described, for example, in the German patentapplications DE 34 07 031 A1 or DE 40 17 940 A1. Normally, the reactionis continued until free isocyanate groups are no longer detectable.

[0081] Viewed in terms of this method, the preparation of theisocyanato-containing polyurethane prepolymers has no special featuresbut instead takes place, for example, as described in the patents EP 0089 497 B1 or EP 0 228 003 B1, by reaction of at least onepolyisocyanate, especially a diisocyanate, with at least one polyol,especially a diol, the isocyanate component being employed in a molarexcess, so as to give terminal free isocyanate groups.

[0082] The preparation of the isocyanato-containing polyurethaneprepolymers is preferably carried out using diisocyanates and, ifdesired, minor amounts of polyisocyanates for the purpose of introducingbranching. In the context of the present invention, minor amounts areamounts which do not bring about gelling of the polyurethane prepolymersin the course of their preparation. Such gelling may also be preventedby using small amounts of monoisocyanates.

[0083] Examples of suitable diisocyanates are isophorone diisocyanate(i.e., 5-isocyanato-1-isocyanatomethyl-1,3,3-trimethylcyclohexane),5-isocyanato-1-(2-isocyanatoeth-1-yl)-1,3,3-trimethylcyclohexane,5-isocyanato-1-(3-isocyanatoprop-1-yl)-1,3,3-trimethylcyclohexane,5-isocyanato-(4-isocyanatobut-1-yl)-1,3,3-trimethylcyclohexane,1-isocyanato-2-(3-isocyanatoprop-1-yl)cyclohexane,1-isocyanato-2-(3-isocyanatoeth-1-yl)cyclohexane,1-isocyanato-2-(4-isocyanatobut-1-yl)cyclohexane,1,2-diisocyanatocyclobutane, 1,3-diisocyanatocyclobutane,1,2-diisocyanatocyclopentane, 1,3-diisocyanatocyclopentane,1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane,1,4-diisocyanatocyclohexane, dicyclohexylmethane 2,4′-diisocyanate,trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylenediisocyanate, hexamethylene diisocyanate, ethylethylene diisocyanate,trimethylhexane diisocyanate, heptanemethylene diisocyanate ordiisocyanates derived from dimeric fatty acids, as marketed under thecommercial designation DDI 1410 by the company Henkel and described inthe patents DO 97/49745 and WO 97/49747, especially2-heptyl-3,4-bis(9-isocyanatononyl)-1-pentylcyclohexane, or 1,2-, 1,4-or 1,3-bis(isocyanatomethyl)cyclohexane, 1,2-, 1,4- or1,3-bis(2-isocyanatoeth-1-yl)cyclohexane,1,3-bis(3-isocyanatoprop-1-yl)cyclohexane, 1,2-, 1,4- or1,3-bis(4-isocyanatobut-1-yl)cyclohexane, liquidbis(4-isocyanatocyclohexyl)methane with a trans/trans content of up to30% by weight, preferably 25% by weight, and in particular 20% byweight, as is described in the patents DE 44 14 032 A1, GB 1 220 717 A1,DE-A-16 18 795 or DE 17 93 785 A1; tolylene diisocyanate, xylylenediisocyanate, bisphenylene diisocyanate, naphthylene diisocyanate ordiphenylmethane diisocyanate.

[0084] Examples of suitable polyisocyanates are the isocyanurates of thediisocyanates described above.

[0085] Examples of highly suitable monoisocyanates are phenylisocyanate, cyclohexyl isocyanate, stearyl isocyanate, vinyl isocyanate,methacryloyl isocyanate and/or1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)benzene (TMI® fromCYTEC).

[0086] Examples of suitable polyols are saturated or olefinicallyunsaturated polyester polyols which are prepared by reacting

[0087] unsulfonated or sulfonated saturated and/or unsaturatedpolycarboxylic acids or their esterifiable derivatives, alone ortogether with monocarboxylic acids, and

[0088] saturated and/or unsaturated polyols, alone or together withmonools.

[0089] Examples of suitable polycarboxylic acids are aromatic, aliphaticand cycloaliphatic polycarboxylic acids. Preference is given to the useof aromatic and/or aliphatic polycarboxylic acids.

[0090] Examples of suitable aromatic polycarboxylic acids are phthalicacid, isophthalic acid, terephthalic acid, phthalic, isophthalic orterephthalic acid monosulfonate, or halophthalic acids, such astetrachlorophthalic or tetrabromophthalic acid, among which isophthalicacid is advantageous and is therefore used with preference.

[0091] Examples of suitable acyclic aliphatic or unsaturatedpolycarboxylic acids are oxalic acid, malonic acid, succinic acid,glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid,sebacic acid, undecanedicarboxylic acid or dodecanedicarboxylic acid, ormaleic acid, fumaric acid or itaconic acid, of which adipic acid,glutaric acid, azelaic acid, sebacic acid, dimeric fatty acids andmaleic acid are advantageous and are therefore used with preference.

[0092] Examples of suitable cycloaliphatic and cyclic unsaturatedpolycarboxylic acids are 1,2-cyclobutanedicarboxylic acid,1,3-cyclobutanedicarboxylic acid, 1,2-cyclopentanedicarboxylic acid,1,3-cyclopentanedicarboxylic acid, hexahydrophthalic acid,1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid,4-methylhexahydrophthalic acid, tricyclodecanedicarboxylic acid,tetrahydrophthalic acid or 4-methyltetrahydrophthalic acid. Thesedicarboxylic acids may be used both in their cis and in their trans formand also as a mixture of both forms.

[0093] Further examples of suitable polycarboxylic acids are polymericfatty acids, especially those having a dimer content of more than 90% byweight, which are also known as dimeric fatty acids.

[0094] Also suitable are the esterifiable derivatives of theabovementioned polycarboxylic acids, such as their monoesters orpolyesters with aliphatic alcohols having 1 to 4 carbon atoms, forexample. It is also possible to use the anhydrides of the abovementionedpolycarboxylic acids, where they exist.

[0095] Together with the polycarboxylic acids it is also possible ifdesired to use monocarboxylic acids, such as, for example, benzoic acid,tert-butylbenzoic acid, lauric acid, isononanoic acid, fatty acids ofnaturally occurring oils, acrylic acid, methacrylic acid, ethacrylicacid or crotonic acid. The preferred monocarboxylic acid used isisononanoic acid.

[0096] Examples of suitable polyols are diols and triols, especiallydiols. Normally, triols are used alongside the diols in minor amounts inorder to introduce branches into the polyester polyols. In the contextof the present invention, minor amounts are amounts which do not causegelling of the polyester polyols during their preparation.

[0097] Examples of suitable diols are ethylene glycol, 1,2- or1,3-propanediol, 1,2-, 1,3- or 1,4-butanediol, 1,2-, 1,3-, 1,4- or1,5-pentanediol, 1,2-, 1,3-, 1,4-, 1,5- or 1,6-hexanediol, neopentylhydroxypivalate, neopentyl glycol, diethylene glycol, 1,2-, 1,3- or1,4-cyclohexanediol, 1,2-, 1,3- or 1,4-cyclohexanedimethanol,trimethylpentanediol, ethylbutylpropanediol, the positionally isomericdiethyloctanediols, 2-butyl-2-ethyl-1,3-propanediol,2-butyl-2-methyl-1,3-propanediol, 2-phenyl-2-methyl-1,3-propanediol,2-propyl-2-ethyl-1,3-propanediol, 2-di-tert-butyl-1,3-propanediol,2-butyl-2-propyl-1,3-propanediol,1-dihydroxymethylbicyclo[2.2.1]heptane, 2,2-diethyl-1,3-propanediol,2,2-dipropyl-1,3-propanediol, 2-cyclohexyl-2-methyl1,3-propanediol,2,5-dimethyl-2,5-hexanediol, 2,5-diethyl-2,5-hexanediol,2-ethyl-5-methyl-2,5-hexanediol, 2,4-dimethyl-2,4-pentanediol,2,3-dimethyl-2,3-butanediol, 1,4-bis(2′-hydroxypropyl)benzene and1,3-bis(2′-hydroxypropyl)benzene.

[0098] Of these diols, 1,6-hexanediol and neopentyl glycol areparticularly advantageous and are therefore used with particularpreference.

[0099] The abovementioned diols may also be used as diols directly toprepare the polyurethane prepolymers.

[0100] Examples of suitable triols are trimethylolethane,trimethylolpropane or glycerol, especially trimethylolpropane.

[0101] The abovementioned triols may also be used as triols directly toprepare the polyurethane prepolymers (cf. EP 0 339 433 A1).

[0102] If desired, minor amounts of monools may also be used. Examplesof suitable monools are alcohols or phenols such as ethanol, propanol,n-butanol, sec-butanol, tert-butanol, amyl alcohols, hexanols, fattyalcohols, allyl alcohol, or phenol.

[0103] The polyester polyols may be prepared in the presence of smallamounts of a suitable solvent as entrainer. Examples of entrainers usedare aromatic hydrocarbons, such as especially xylene and(cyclo)-aliphatic hydrocarbons, e.g., cyclohexane or methylcyclohexane.

[0104] Further examples of suitable polyols are polyester diols whichare obtained by reacting a lactone with a diol. They are notable for thepresence of terminal hydroxyl groups and repeating polyester fractionsof the formula —(—CO—(CHR)_(m)—CH₂—O—)—. Here, the index m is preferablyfrom 4 to 6 and the substituent R is hydrogen or an alkyl, cycloalkyl,or alkoxy radical. No substituent contains more than 12 carbon atoms.The total number of carbon atoms in the substituent does not exceed 12per lactone ring. Examples are hydroxycaproic acid, hydroxybutyric acid,hydroxydecanoic acid, and/or hydroxystearic acid.

[0105] Preferred for the preparation of the polyester diols is theunsubstituted epsilon-caprolactone, where m is 4 and all substituents Rare hydrogen. The reaction with lactone is started by low molecular masspolyols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, ordimethylolcyclohexane. It is also possible, however, to react otherreaction components, such as ethylenediamine, alkyldialkanolamines, orelse urea, with caprolactone. Other suitable diols of relatively highmolecular mass are polylactam diols, which are prepared by reacting, forexample, epsilon-caprolactam with low molecular mass diols.

[0106] Further examples of suitable polyols include polyether polyols,especially those having a number-average molecular weight of from 400 to5000, in particular from 400 to 3000. Examples of highly suitablepolyether diols are polyether diols of the general formulaH—(—O—(CHR¹)_(o)—)_(p)OH, where the substituent R¹ is hydrogen or alower, unsubstituted or substituted alkyl radical, the index o is from 2to 6, preferably from 3 to 4, and the index p is from 2 to 100,preferably from 5 to 50. Especially suitable examples are linear orbranched polyether diols such as poly(oxyethylene) glycols,poly(oxypropylene) glycols, and poly(oxybutylene) glycols.

[0107] By means of the polyether diols it is possible to introduce thenonionic hydrophilic functional groups (f3), or a part thereof, into themain chain(s) of the polyurethane prepolymers.

[0108] For the preparation of the polyurethane prepolymers it is alsopossible to use further starting compounds in order to varyadvantageously the profile of properties of the polyurethanes of theinvention and of the polymer mixtures of the invention.

[0109] Where the polyurethanes and polymer mixtures of the invention areto have self-crosslinking properties, it is possible to use at least onecompound containing at least one blocked isocyanate group and at leasttwo isocyanate-reactive functional groups. Examples of suitableisocyanate-reactive groups are —SH, —NH₂, >NH, —OH, —O—(CO)—NH—(CO)—NH₂or —O—(CO)—NH₂, of which the primary and secondary amino groups and thehydroxyl group are of advantage and the hydroxyl groups are ofparticular advantage. Examples of suitable blocking agents are theblocking agents known from the U.S. Pat. No. 4,444,954 A1, of which theoximes and ketoximes xiii), especially the ketoximes xiii), specificallymethyl ethyl ketoxime, offer particular advantages and are thereforeused with particular preference. However, the blocked isocyanate groupsmay also result from the reaction of the free isocyanate groups of thepolyurethane prepolymer with the blocking agents.

[0110] For introducing olefinically unsaturated groups—where used—it ispossible to use at least one compound containing at least oneolefinically unsaturated group and at least two isocyanate-reactivefunctional groups. Examples of suitable isocyanate-reactive functionalgroups are those described above. Examples of suitable olefinicallyunsaturated groups and compounds for introducing them are described inthe patent applications and patents DE 197 22 862 C2, DE 196 45 761 A1,EP 0 401 565 A1, EP 0 522 420 A1, EP 0 522 419 A2, EP 0 755 946 A1, EP 0608 021 A1, EP 0 708 788 A1 or EP 0 730 613 A1 and also in the Germanpatent applications DE 199 53 446.2, DE 199 53 445.2 or DE 199 53 203.6,unpublished at the priory date of this present specification.Alternatively, the olefinically unsaturated groups may be introduced byway of the above-described compounds containing at least oneolefinically unsaturated group and an isocyanate group.

[0111] For the preparation of the hydrophilic polyurethanes of theinvention, compounds containing at least one hydrophilic functionalgroup and at least one isocyanate-reactive functional group areadditionally incorporated into the isocyanato-containing polyurethaneprepolymers.

[0112] The introduction of hydrophilic functional (potentially) cationicgroups (f1) into the polyurethane prepolymers takes place by way of theincorporation of compounds which contain in the molecule at least one,especially two, isocyanate-reactive groups and at least one groupcapable of forming cations; the amount to be used may be calculated fromthe target amine number.

[0113] Suitable isocyanate-reactive groups are those described above,especially hydroxyl groups and also primary and/or secondary aminogroups, of which the hydroxyl groups are used with preference.

[0114] Examples of suitable compounds of this kind are2,2-dimethylolethyl- or -propylamine blocked with a ketone, theresultant ketoxime group being hydrolyzed again prior to the format-ionof the cationic group (f1), or N,N-dimethyl-, N,N-diethyl- orN-methyl-N-ethyl-2,2-dimethylolethyl- or -propylamine.

[0115] The introduction of hydrophilic functional (potentially) anionicgroups (f2) into the polyurethane prepolymers takes place by way of theincorporation of compounds which contain in the molecule at least oneisocyanate-reactive group and at least one group capable of forminganions; the amount to be used may be calculated from the target acidnumber.

[0116] Examples of suitable compounds of this kind are those containingtwo isocyanate-reactive groups in the molecule. Here again, suitableisocyanate-reactive groups are those described above. Accordingly it ispossible, for example, to use alkanoic acids having two substituents onthe α carbon atom. The substituent may be a hydroxyl group, an alkylgroup, or, preferably, an alkylol group. These alkanoic acids have atleast one, generally from 1 to 3, carboxyl groups in the molecule. Theyhave 2 to about 25, preferably 3 to 10, carbon atoms. Examples ofsuitable alkanoic acids are dihydroxypropionic acid, dihydroxysuccinicacid, and dihydroxybenzoic acid. A particularly preferred group ofalkanoic acids are the alpha, alpha-dimethylolalkanoic acids of thegeneral formula R²—C(CH₂OH)₂COOH, R² being a hydrogen atom or an alkylgroup having up to about 20 carbon atoms. Examples of especiallysuitable alkanoic acids are 2,2-dimethylolacetic acid,2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, and2,2-dimethylolpentanoic acid. The preferred dihydroxyalkanoic acid is2,2-dimethylolpropionic acid. Examples of compounds containing aminogroups are α, δ-diaminovaleric acid, 3,4-diaminobenzoic acid,2,4-diaminotoluenesulfonic acid, and 2,4-diaminodiphenyl ether sulfonicacid.

[0117] Hydrophilic functional nonionic poly(oxyalkylene) groups (f3) maybe introduced as lateral or terminal groups into the polyurethanemolecules. For this purpose it is possible to use not only theabove-described polyether diols but also, for example,alkoxypoly(oxyalkylene) alcohols having the general formulaR³O—(—CH₂—CHR⁴—O—)_(r)H, where R³ is an alkyl radical having 1 to 6carbon atoms, R⁴ is a hydrogen atom or an alkyl radical having 1 to 6carbon atoms, and the index r is a number between 20 and 75 (cf. thepatent applications EP 0 354 261 A1 or EP 0 424 705 A2).

[0118] The hydrophilic functional groups (f1) or (f2) are to be selectedso as to rule out the possibility of any disruptive reactions, such as,for instance, salt formation or crosslinking with the functional groupsthat may be present in the other starting compounds and/or constituentsof the polyurethanes of the invention or of polymer mixtures of theinvention, of the dispersions of the invention, of the coating materialsof the invention, of the sealing compounds of the invention, or of theadhesives of the invention. The skilled worker will therefore be able tomake the selection in a simple manner on the basis of his or herknowledge in the art.

[0119] Of these hydrophilic functional (potentially) ionic groups (f1)and (f2) and the hydrophilic functional nonionic groups (f3), the(potentially) anionic groups (f2) are advantageous and are thereforeused with particular preference.

[0120] The preparation of the isocyanato-containing polyurethaneprepolymers from the starting compounds described above likewise has nospecial features in terms of method but instead takes place in bulk orin an inert organic medium, preferably in an inert organic medium, inwhich case use is made preferably of polar organic solvents, especiallywater miscible solvents such as ketones, esters, ethers, cyclic amidesor sulfoxides. The reaction in this case may take place in two or morestages or in one stage. The essential factor is that the reaction iscarried out until the amount of free isocyanate groups is constant.

[0121] The polyurethanes of the invention may be isolated from thesolutions or dispersions in which they are produced and put to a verywide variety of end uses, especially in solvent-containing, water- andsolvent-free pulverulent solid or water- and solvent-free liquid coatingmaterials, adhesives and sealing compounds. Thus, they are suitable forpreparing pigmented or unpigmented, conventional or aqueous coatingmaterials, powder coating materials, powder slurry coating materials, or100% systems. In particular, however, they serve to prepare the polymermixtures of the invention.

[0122] For this purpose, at least one olefinically unsaturated monomer(a) is polymerized in the presence of at least one polyurethane of theinvention in organic solution or in a dispersion.

[0123] Conducting the polymerization in organic solution has theadvantage that this process step can be carried out directly after thepreparation of the polyurethane of the invention, in other words withouta dispersing step in between. In certain circumstances, this facilitatesthe isolation of the polymer mixtures of the invention for particularend uses. In this case, the customary and known methods of solutionpolymerization may be employed.

[0124] In accordance with the invention, it is of advantage topolymerize the monomer (a) or the monomers (a) in the dispersion of atleast one polyurethane of the invention in an aqueous medium, especiallywhen the resulting polymer mixtures of the invention are used to prepareaqueous coating materials, adhesives and sealing compounds.

[0125] The aqueous medium contains essentially water. The aqueous mediummay include minor amounts of organic solvents, neutralizing agents,crosslinking agents and/or customary coatings additives and/or otherdissolved solid, liquid or gaseous organic and/or inorganic substancesof low and/or high molecular mass. In the context of the presentinvention, the term “minor amount” means an amount which does not changethe aqueous nature of the aqueous medium. The aqueous medium, however,may also comprise just water.

[0126] For the purpose of dispersion, the hydrophilic polyurethanes ofthe invention, containing the above-described (potentially) ionichydrophilic functional groups (f1) or (f2), are neutralized with atleast one of the above-described neutralizing agents and subsequentlyare dispersed. In the case of the hydrophilic thio polyurethanes of theinvention which contain only the nonionic hydrophilic functional groups(f3), the use of neutralizing agents is unnecessary.

[0127] It is also possible to disperse the hydrophobic polyurethanes ofthe invention in an aqueous medium. Advantageously, this is carried outin a strong shear field. Viewed in terms of its method, this process hasno special features, but instead may take place, for example, inaccordance with the microfluidizer dispersion techniques described inthe European patent application EP 0 401 565 A1.

[0128] Examples of monomers (a) suitable for preparing the polymermixtures of the invention are the following:

[0129] Monomers (a1):

[0130] Hydroxyalkyl esters of acrylic acid, methacrylic acid or anotheralpha,beta-ethylenically unsaturated carboxylic acid which are derivedfrom an alkylene glycol which is esterified with the acid, or areobtainable by reacting the acid with alkylene oxide, especiallyhydroxyalkyl esters of acrylic acid, methacrylic acid, crotonic acid orethacrylic acid in which the hydroxyalkyl group contains up to 20 carbonatoms, such as 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl,3-hydroxybutyl, 4-hydroxybutyl acrylate, methacrylate, ethacrylate orcrotonate; 1,4-bis(hydroxymethyl)cyclohexane,octahydro-4,7-methano-1H-indenedimethanol or methylpropanediolmonoacrylate, monomethacrylate, monoethacrylate or monocrotonate; orreaction products of cyclic esters, such as ε-caprolactone, for example,and these hydroxyalkyl esters; or olefinically unsaturated alcohols suchas allyl alcohol or polyols such as trimethylolpropane monoallyl ordiallyl ether or pentaerythritol monoallyl, diallyl or triallyl ether.These higher-functional monomers (a1) are generally used only in minoramounts. In the context of the present invention, minor amounts ofhigher-functional monomers here are amounts which do not result incrosslinking or gelling of the polyacrylate resins unless the polymermixtures of the invention are to be in the form of crosslinked microgelparticles.

[0131] Monomers (a2):

[0132] (Meth)acrylic, crotonic or ethacrylic alkyl or cycloalkyl estershaving up to 20 carbon atoms in the alkyl radical, especially methyl,ethyl, propyl, n-butyl, sec-butyl, tert-butyl, hexyl, ethylhexyl,stearyl and lauryl acrylate, methacrylate, crotonate or ethacrylate;cycloaliphatic (meth)acrylic, crotonic or ethacrylic esters, especiallycyclohexyl, isobornyl, dicyclopentadienyl,octahydro-4,7-methano-1H-indenemethanol or tert-butylcyclohexyl(meth)acrylate, crotonate or ethacrylate; (meth)acrylic, crotonic orethacrylate oxaalkyl esters or oxacycloalkyl esters such asethyltriglycol (meth)acrylate and methoxyoligoglycol (meth)acrylatehaving a molecular weight Mn of preferably 550; or other ethoxylatedand/or propoxylated hydroxyl-free (meth)acrylic acid, crotonic acid orethacrylic acid derivatives. These may include, in minor amounts,higher-functional (meth)acrylic, crotonic or ethacrylic alkyl orcycloalkyl esters such as ethylene glycol, propylene glycol, diethyleneglycol, dipropylene glycol, butylene glycol, 1,5-pentanediol,1,6-hexanediol, octahydro-4,7-methano-1H-indenedimethanol orcyclohexane-1,2-, -1,3- or -1,4-diol di(meth)acrylate;trimethylolpropane di- or tri-(meth)acrylate; or pentaerythritol di-,tri- or tetra(meth)acrylate and the analogous ethacrylates orcrotonates. In the context of the present invention, minor amounts ofhigher-functional monomers (a2) here are amounts which do not result incrosslinking or gelling of the polyacrylate resins unless the polymermixtures of the invention are to be in the form of crosslinked microgelparticles.

[0133] Monomers (a3):

[0134] Ethylenically unsaturated monomers which carry at least one acidgroup, preferably a carboxyl group, per molecule, or a mixture of suchmonomers. As components (a3) it is particularly preferred to use acrylicacid and/or methacrylic acid. It is also possible, however, to use otherethylenically unsaturated carboxylic acids having up to 6 carbon atomsin the molecule. Examples of such acids are ethacrylic acid, crotonicacid, maleic acid, fumaric acid, and itaconic acid. It is also possibleto use ethylenically unsaturated sulfonic or phosphonic acids, and/ortheir partial esters, as component (a3). Further suitable monomers (a3)include mono(meth)acryloyloxyethyl maleate, succinate, and phthalate,and also vinylbenzoic acid (all isomers); alpha-methylvinylbenzoic acid(all isomers) or vinylbenzenesulfonic acid (all isomers).

[0135] Monomers (a4):

[0136] Vinyl esters of alpha-branched monocarboxylic acids having 5 to18 carbon atoms in the molecule. The branched monocarboxylic acids maybe obtained by reacting formic acid or carbon monoxide and water witholefins in the presence of a liquid, strongly acidic catalyst; theolefins may be cracking products from paraffinic hydrocarbons, such asmineral oil fractions, and may contain both branched and straight-chainacyclic and/or cycloaliphatic olefins. In the reaction of such olefinswith formic acid and/or with carbon monoxide and water, a mixture ofcarboxylic acids is formed in which the car-boxyl groups are locatedpredominantly on a quaternary carbon atom. Other olefinic startingmaterials are, for example, propylene trimer, propylene tetramer, anddiisobutylene. Alternatively, the vinyl esters may be prepared in aconventional manner from the acids, for example, by reacting the acidwith acetylene. Particular preference—owing to their readyavailability—is given to the use of vinyl esters of saturated aliphaticmono-carboxylic acids having 9 to 11 carbon atoms and being branched onthe alpha carbon atom.

[0137] Monomers (a5):

[0138] Reaction product of acrylic acid and/or methacrylic acid with theglycidyl ester of an alpha-branched monocarboxylic acid having 5 to 18carbon atoms per molecule. The reaction of the acrylic or methacrylicacid with the glycidyl ester of a carboxylic acid having a tertiaryalpha carbon atom may take place before, during or after thepolymerization reaction. As component (a5) it is preferred to use thereaction product of acrylic and/or methacrylic acid with the glycidylester of Versatic® acid. This glycidyl ester is obtainable commerciallyunder the name Cardura® E10. For further details, reference is made toRömpp Lexikon Lacke und Druckfarben, Georg Thieme Verlag, Stuttgart,N.Y., 1998, pages 605 and 606.

[0139] Monomers (a6):

[0140] Ethylenically unsaturated monomers essentially free from acidgroups, such as

[0141] olefins such as ethylene, propylene, 1-butene, 1-pentene,1-hexene, cyclohexene, cyclopentene, norbornene, butadiene, isoprene,cyclopentadiene and/or dicyclopentadiene;

[0142] (meth)acrylamides such as (meth)acrylamide, N-methyl-,N,N-dimethyl-, N-ethyl-, N,N-diethyl-, N-propyl-, N,N-dipropyl,N-butyl-, N,N-dibutyl-, N-cyclohexyl- and/orN,N-cyclohexyl-methyl-(meth)acrylamide and/or N-methylol-,N,N-dimethylol-, N-methoxymethyl-, N,N-di(methoxymethyl)-,N-ethoxymethyl- and/or N,N-di(ethoxyethyl)-(meth)acrylamide, which areused in particular when the polymer mixtures of the invention are tohave self-crosslinking properties;

[0143] monomers containing epoxide groups, such as the glycidyl ester ofacrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, maleicacid, fumaric acid and/or itaconic acid;

[0144] aminoethyl acrylate, aminoethyl methacrylate, allylamine orN-methyliminoethyl acrylate;

[0145] N,N-di(methoxymethyl)aminoethyl acrylate or methacrylate orN,N-di(butoxymethyl)aminopropyl acrylate or methacrylate;

[0146] acryloyloxy- or methacryloyloxy-ethyl-, -propyl- or-butylcarbamate or -allophanate; further examples of suitable monomerscontaining carbamate groups are described in the patents U.S. Pat. No.3,479,328 A1, U.S. Pat. No. 3,674,838 A1, U.S. Pat. No. 4,126,747 A1,U.S. Pat. No. 4,279,833 A1 or U.S. Pat. No. 4,340,497 A1;

[0147] vinylaromatic hydrocarbons, such as styrene, alpha-alkylstyrenes,especially alpha-methylstyrene, arylstyrenes, especiallydiphenylethylene, and/or vinyltoluene;

[0148] nitriles such as acrylonitrile and/or methacrylonitrile;

[0149] vinyl compounds such as vinyl chloride, vinyl fluoride,vinylidene dichloride, vinylidene difluoride; N-vinylpyrrolidone; vinylethers such as ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinylether, n-butyl vinyl ether, isobutyl vinyl ether and/or vinyl cyclohexylether; vinyl esters such as vinyl acetate, vinyl propionate, vinylbutyrate, vinyl pivalate, vinyl esters of Versatic® acids, which aremarketed under the brand name VeoVa® by the company Deutsche ShellChemie (for further details, reference is made to, Römpp Lexikon Lackeund Druckfarben, Georg Thieme Verlag, Stuttgart, N.Y., 1998, page 598and also pages 605 and 606), and/or the vinyl ester of2-methyl-2-ethylheptanoic acid; and/or

[0150] polysiloxane macromonomers having a number-average molecularweight Mn of from 1000 to 40,000, preferably from 2000 to 20,000, withparticular preference from 2500 to 10,000, and in particular from 3000to 7000, and having on average from 0.5 to 2.5, preferably from 0.5 to1.5, ethylenically unsaturated double bonds per molecule, as aredescribed in DE 38 07 571 A1 on pages 5 to 7, in DE 37 06 095 A1 incolumns 3 to 7, in EP 0 358 153 B1 on pages 3 to 6, in U.S. Pat. No.4,754,014 A1 in columns 5 to 9, in DE 44 21 823 A1, or in theinternational patent application WO 92/22615 on page 12, line 18 to page18, line 10, or acryloxysilane-containing vinyl monomers, preparable byreacting hydroxy-functional silanes with epichlorohydrin and thenreacting the reaction product with methacrylic acid and/or hydroxyalkylesters of (meth)acrylic acid.

[0151] From these suitable monomers (a) described above by way ofexample, the skilled worker is easily able to select, on the basis oftheir known physicochemical properties and reactivities, the monomers(a) that are particularly suitable for the intended use in question. Forexample, he or she may select monomers (a1), (a3) and/or (a6) whichintroduce reactive functional groups which are necessary for thermalcrosslinking. If desired, he or she may for this purpose conduct a fewpreliminary range-finding experiments. In particular, he or she will becareful to ensure that monomers (a) contain no functional groups,especially (potentially) ionic functional groups, which enter intounwanted interactions and/or chemical reactions with the (potentially)ionic functional groups in the hydrophilic polyurethanes of theinvention.

[0152] Where the polymer mixtures of the invention are present in theform of crosslinked microgel particles or comprise such particles,higher-functional monomers (a), especially the above-describedhigher-functional monomers (a1) and/or (a2), are used in amounts whichlead to targeted crosslinking of the grafted and/or ungrafted(co)polymers.

[0153] In accordance with the invention, particular advantages result ifthe monomers (a) are selected such that the profile of properties of thegrafted (co)polymers is determined essentially by the above-described(meth)acrylate monomers (a), the other monomers (a) advantageouslyproviding broad variation of this profile of properties.

[0154] In accordance with the invention, very particular advantagesresult from using mixtures of the monomers (a1), (a2) and (a6) and also,if desired, (a3).

[0155] Viewed in terms of method, the preparation of the polymermixtures of the invention has no special features but instead takesplace in accordance with the customary and known methods of free-radicalsolution or emulsion, miniemulsion or microemulsion polymerization inthe presence of at least one polymerization initiator such as isdescribed, for example, in the patents and patent applications DE 197 22862 C2, DE 196 45 761 A1, EP 0 401 565 A1, EP 0 522 420 A1, EP 0 522 419A2, EP 0 755 946 A1, EP 0 608 021 A1, EP 0 708 788 A1 or EP 0 730 613A1, and in the German patent applications DE 199 53 446.2, DE 199 53445.2 or DE 199 53 203.6, unpublished at the priority date of thepresent specification.

[0156] In the case of the emulsion polymerization, the monomers (a) mayalso be brought into the form of a preemulsion with the aid of a portionof a polyurethane dispersion of the invention and water, thispreemulsion then being metered slowly into an initial charge in whichthe actual emulsion polymerization takes place.

[0157] Examples of suitable polymerization initiators are initiatorswhich form free radicals, such as dialkyl peroxides, such asdi-tert-butyl peroxide or dicumyl peroxide; hydroperoxides, such ascumene hydroperoxide or tert-butyl hydroperoxide; peresters, such astert-butyl perbenzoate, tert-butyl perpivalate, tert-butylper-3,5,5-trimethylhexanoate, or tert-butyl per-2-ethylhexanoate;potassium, sodium or ammonium peroxodisulfate; azo dinitriles such asazobisiso-butyronitrile; C—C-cleaving initiators such as benzpinacolsilyl ether; or a combination of a nonoxidizing initiator with hydrogenperoxide. Preference is given to the use of water-insoluble initiators.The initiators are used preferably in an amount of from 0.1 to 25% byweight, with particular preference from 0.75 to 10% by weight, based onthe overall weight of the monomers (a).

[0158] In the solutions or the aqueous emulsions, the monomers (a) arethen polymerized with the aid of the abovementioned radical-forminginitiators at temperatures from 0 to 95° C., preferably from 40 to 95°C., and when using redox systems at temperatures from 30 to 70° C. Whenoperating under superatmospheric pressure, the emulsion polymerizationmay also be conducted at temperatures above 100° C. The same applies tosolution polymerization if relatively high-boiling organic solventsand/or superatmospheric pressure are/is employed.

[0159] It is preferred to commence the initiator feed a certain time,generally from about 1 to 15 minutes, before the feed of the monomers.Preference is also given to a process wherein the addition of initiatoris commenced at the same point in time as the addition of the monomersand is ended about half an hour after the addition of the monomers hasbeen ended. The initiator is preferably added in a constant amount perunit time. Following the end of addition of initiator, the reactionmixture is held at polymerization temperature until (generally 1 to 1.5hours) all of the monomers used have undergone essentially completereaction. “Essentially complete reaction” is intended to denote thatpreferably 100% by weight of the monomers used have been converted butthat it is also possible for a low residual monomer content of not morethan up to about 0.5% by weight, based on the weight of the reactionmixture, to remain unconverted.

[0160] Suitable reactors for the (co)polymerization processes are thecustomary and known stirred vessels, cascades of stirred vessels, tubereactors, loop reactors or Taylor reactors, as described, for example,in the patent DE 1 071 241 B1, the patent applications EP 0 498 583 A1or DE 198 28 742 A1, or in the article by K. Kataoka in ChemicalEngineering Science, Volume 50, No. 9, 1995, pages 1409 to 1416.

[0161] In accordance with the invention it is of advantage to select thepolyurethanes of the invention and the monomers (a) such that thegrafted-on (co)polymer and/or the grafted hydrophilic polyurethane ofthe invention, but especially the grafted hydrophilic polyurethane ofthe invention, contain/contains hydrophilic functional groups,especially carboxylic acid groups and/or carboxylate groups (f2).

[0162] In the graft copolymers of the invention which are or may bepresent in the polymer mixtures of the invention, the proportion ofgraft base or core (polyurethane of the invention) to graft sheath orshell may vary extremely widely, which is a particular advantage of thepolymer mixtures of the invention.

[0163] Further particular advantages result from the inventivelypreferred use of (potentially) anionic hydrophilic functional groups(f2), especially carboxylic acid groups, since in the graft copolymersof the invention the ratio of acid number of the shell to acid number ofthe core may likewise be varied widely.

[0164] The polymer mixtures of the invention may be isolated from thesolutions or dispersions in which they are produced and put to a verywide variety of end uses, especially in solvent-containing, water- andsolvent-free pulverulent solid or water- and solvent-free liquid coatingmaterials, adhesives and sealing compounds. They are particularlysuitable for preparing pigmented or unpigmented, conventional or aqueouscoating materials, powder coating materials, powder slurry coatingmaterials, or 100% systems.

[0165] In accordance with the invention, however, it is of advantage touse the dispersions of the invention, which in the procedure accordingto the invention are obtained either as primary dispersions or assecondary dispersions by dispersing the solutions of the polymermixtures of the invention in water, as they are for the preparation ofaqueous coating materials, adhesives and sealing compounds of theinvention or as aqueous coating materials, adhesives and sealingcompounds. In the case of use as coating materials, they exhibitoutstanding film-forming properties.

[0166] The aqueous coating materials, adhesives and sealing compounds ofthe invention may be curable physically, thermally, or thermally andwith actinic radiation.

[0167] In the context of the present invention, the term “physicalcuring” means the curing of a layer of a coating material, of anadhesive or of a sealing compound by the formation of a film as a resultof loss of solvent from the coating material, adhesive or sealingcompound, linking taking place within the coating by way of formation ofloops of the polymer molecules of the binders (regarding the term cf.Römpp Lexikon Lacke und Druckfarben, Georg Thieme Verlag, Stuttgart,N.Y., 1998, “Binders”, pages 73 and 74). Alternatively, the formation ofa film takes place by way of the coalescence of binder particles (cf.Römpp Lexikon Lacke und Druckfarben, Georg Thieme Verlag, Stuttgart,N.Y., 1998, “Curing”, pages 274 and 275). Normally, no crosslinkingagents are required for this purpose. If desired, the physical curingcan be assisted by atmospheric oxygen, heat, or exposure to actinicradiation.

[0168] In the context of the present invention, the term“self-crosslinking” denotes the property of a binder to undergocrosslinking reactions with itself. A precondition for this is that thebinder already contains both types of complementary reactive functionalgroups necessary for crosslinking. Externally cross-linking, on theother hand, is used to denote those coating materials, adhesives andsealing compounds in which one type of the complementary reactivefunctional groups is present in the binder and the other type in ahardener, curing agent or crosslinking agent. For further details, referto Römpp Lexikon Lacke und Druckfarben, Georg Thieme Verlag, Stuttgart,N.Y., 1998, “Curing”, pages 274 to 276, especially page 275, at thebottom.

[0169] In the context of the present invention, actinic radiation iselectromagnetic radiation, such as near infrared (NIR), visible light,UV radiation or X-radiation, especially UV radiation, and corpuscularradiation such as electron beams. If thermal curing and curing withactinic radiation are employed conjointly, the terms “dual cure” and“dual-cure coating material”, “dual-cure adhesive” or “dual-cure sealingcompound” are also used.

[0170] In addition to the polymer mixtures of the invention, the aqueousadhesives of the invention may include further suitable, customary andknown constituents in effective amounts. Examples of suitableconstituents are the crosslinking agents and additives described below,provided they are suitable for the preparation of adhesives.

[0171] Likewise, in addition to the polymer mixtures of the inventionthe aqueous sealing compounds of the invention may include furthersuitable, customary and known constituents in effective amounts.Examples of suitable constituents are, again, the crosslinkers andadditives described below, provided they are suitable for thepreparation of sealing compounds.

[0172] The inventive primary dispersions and secondary dispersions ofthe polymer mixtures of the invention are primarily suitable forpreparing aqueous coating materials, especially aqueous surface coatingmaterials. Examples of aqueous surface coating materials of theinvention are surfacers, solid-color topcoats, aqueous basecoats, andclearcoats. The primary dispersions and secondary dispersions of theinvention exhibit very particular advantages when used to prepareaqueous basecoat materials.

[0173] In the aqueous basecoat materials, the polymer mixtures of theinvention are advantageously present in an amount of from 1.0 to 50,preferably from 2.0 to 40, with particular preference from 3.0 to 35,with very particular preference from 4.0 to 30, and in particular from5.0 to 25, % by weight, based in each case on the overall weight of therespective aqueous basecoat material.

[0174] The further essential constituent of the aqueous basecoatmaterial of the invention is at least one color and/or effect pigment.The pigments may consist of organic or inorganic compounds. Examples ofsuitable effect pigments are metal flake pigments such as commercialaluminum bronzes, aluminum bronzes chromated in accordance with DE 36 36183 A1, and commercial stainless steel bronzes and also nonmetalliceffect pigments, such as pearlescent pigments and interference pigments,for example, platelet-shaped effect pigments based on iron oxide havinga color from pink to brownish red, or liquid-crystalline effectpigments. For further details, reference is made to Römpp Lexikon Lackeund Druckfarben, Georg Thieme Verlag, 1998, page 176 “Effect Pigments”and pages 380 and 381 “Metal Oxide-Mica Pigments” to “Metal Pigments”and to the patent applications and patents DE 36 36 156 A1, DE 37 18 446A1, DE 37 19 804 A1, DE 39 30 601 A1, EP 0 068 311 A1, EP 0 264 843 A1,EP 0 265 820 A1, EP 0 283 852 A1, EP 0 293 746 A1, EP 0 417 567 A1, U.S.Pat. No. 4,828,826 A or U.S. Pat. No. 5,244,649 A.

[0175] Examples of suitable inorganic color pigments are white pigmentssuch as titanium dioxide, zinc white, zinc sulfide or lithopones; blackpigments such as carbon black, iron manganese black or spinel black;color pigments such as chromium oxide, chromium oxide hydrate green,cobalt green or ultramarine green, cobalt blue, ultramarine blue ormanganese blue, ultramarine violet or cobalt violet and manganeseviolet, red iron oxide, cadmium sulfoselenide, molybdate red orultramarine red; brown iron oxide, mixed brown, spinel phases andcorundum phases or chromium orange; or yellow iron oxide, nickeltitanium yellow, chromium titanium yellow, cadmium sulfide, cadmium zincsulfide, chromium yellow or bismuth vanadate.

[0176] Examples of suitable organic color pigments are monoazo pigments,disazo pigments, anthraquinone pigments, benzimidazole pigments,quinacridone pigments, quinophthalone pigments, diketopyrrolopyrrolepigments, dioxazine pigments, indanthrone pigments, isoindolinepigments, isoindolinone pigments, azomethine pigments, thioindigopigments, metal complex pigments, perinone pigments, perylene pigments,phthalocyanine pigments or aniline black.

[0177] For further details, reference is made to Römpp Lexikon Lacke undDruckfarben, Georg Thieme Verlag, 1998, pages 180 and 181, “Iron BluePigments” to “Iron Oxide Black”, pages 451 to 453, “Pigments” to“Pigment Volume Concentration”, page 563, “Thioindigo Pigments”, page567, “Titanium Dioxide Pigments”, pages 400 and 467, “NaturallyOccurring Pigments”, page 459 “Polycyclic Pigments”, page 52,“Azomethine Pigments”, “Azopigments”, and page 379, “Metal ComplexPigments”.

[0178] The aqueous basecoat material may comprise at least onecrosslinker having the complementary reactive functional groupsnecessary for thermal crosslinking.

[0179] Examples of suitable crosslinkers are amino resins, as describedfor example in Römpp Lexikon Lacke und Druckfarben, Georg Thieme Verlag,1998, page 29, “Amino Resins”, in the textbook “Lackadditive” [Additivesfor Coatings] by Johan Bieleman, Wiley-VCH, Weinheim, N.Y., 1998, page242 ff., in the book “Paints, Coatings and Solvents”, second completelyrevised edition, Edit. D. Stoye and W. Freitag, Wiley-VCH, Weinheim,N.Y., 1998, page 80 ff., in the patents U.S. Pat. No. 4,710,542 A or EP0 245 700 A1, and in the article by B. Singh and co-workers“Carbamylmethylated Melamines, Novel Crosslinkers for the CoatingsIndustry”, in Advanced Organic Coatings Science and Technology Series,1991, volume 13, pages 193 to 207; carboxyl-containing compounds orresins, as described for example in the patent DE 196 52 813 A1, resinsor compounds containing epoxide groups, as described for example in thepatents EP 0 299 420 A1, DE 22 14 650 B1, DE 27 49 576 B1, U.S. Pat. No.4,091,048 A or U.S. Pat. No. 3,781,379 A; blocked polyisocyanates, asdescribed for example in the patents U.S. Pat. No. 4,444,954 A1, DE 19617 086 A1, DE 196 31 269 A1, EP 0 004 571 A1 or EP 0 582 051 A1; and/ortris(alkoxy-carbonylamino)triazines, as described in the patents U.S.Pat. No. 4,939,213 A, U.S. Pat. No. 5,084,541 A, U.S. Pat. No. 5,288,865A or EP 0 604 922 A.

[0180] The use of crosslinkers can be omitted if the polymer mixtures ofthe invention that are present in the aqueous basecoats haveself-crosslinking properties or crosslink physically.

[0181] In addition to the constituents described above, the aqueousbasecoat material of the invention may include customary and knownbinders and/or additives in effective amounts.

[0182] Examples of customary and known binders are oligomeric andpolymeric, thermally curable poly(meth)acrylates or acrylate copolymerswhich are linear and/or branched and/or of blocklike, comblike and/orrandom construction, especially the polyesters described in the patentDE 197 36 535 A1, in particular those described in the patents DE 40 09858 A1 or DE 44 37 535 A1, alkyds, acrylated polyesters, polylactones,polycarbonates, polyethers, epoxy resin-amine adducts, (meth)acrylatediols, partially hydrolyzed polyvinyl esters, polyurethanes andacrylated polyurethanes, such as those described in the patentapplications EP 0 521 928 A1, EP 0 522 420 A1, EP 0 522 419 A1, EP 0 730613 A1 or DE 44 37 535 A1, or polyureas, or binders curable with actinicradiation, as described for example in the German patent application DE198 35 206 A1.

[0183] Examples of suitable additives are organic and inorganic fillers,thermally curable reactive diluents or reactive diluents curable withactinic radiation (cf. Römpp Lexikon Lacke und Druckfarben, Stuttgart,N.Y., 1998, page 491), low-boiling organic solvents and/or high-boilingorganic solvents (“long solvents”), UV absorbers, light stabilizers,free-radical scavengers, thermally labile free-radical initiators,photoinitiators, crosslinking catalysts, deaerating agents, slipadditives, polymerization inhibitors, defoamers, emulsifiers, wettingagents, adhesion promoters, leveling agents, film-forming auxiliaries,rheology control additives, or flame retardants. Further examples ofsuitable coatings additives are described in the textbook “Lackadditive”by Johan Bieleman, Wiley-VCH, Weinheim, N.Y., 1998.

[0184] The preparation of the aqueous basecoat material of the inventionhas no special features but instead takes place in a customary and knownmanner by mixing the constituents described above in suitable mixingequipment such as stirred vessels, dissolvers, stirred mills, staticmixers, toothed-wheel dispersers or extruders by the processes suitablefor preparing the respective aqueous basecoat materials.

[0185] Of course, the above-described pigments, crosslinkers and otheradditives, and also the above-described methods, may also be employed toprepare the adhesives and sealing compounds of the invention.

[0186] The aqueous basecoat material is outstandingly suitable for theproduction of color and/or effect multicoat systems by the wet-on-wettechnique, in which an aqueous basecoat film is applied, dried andovercoated with a clearcoat film, after which aqueous basecoat film andclearcoat film are cured together. As is known, this process is usedwith advantage in automobile OEM finishing and refinishing.

[0187] Owing to their particularly advantageous properties, however, thecoating materials of the invention are, moreover, also suitable for thecoating of interior and exterior architecture, for the coating offurniture, windows or doors, and for industrial coating, including coilcoating, container coating, and the impregnation or coating ofelectrical components. In the context of industrial coating, they aresuitable for coating virtually all parts for private or industrial use,such as radiators, domestic appliances, small metal parts such as screwsand nuts, hubcaps, wheel rims, packaging, or electrical components suchas motor windings or transformer windings.

[0188] The adhesives and sealing compounds of the invention areoutstandingly suitable for the preparation of adhesive films and sealswhich even under extreme and/or rapidly changing climatic conditions,persistently, are of particularly high bond strength and sealing power.

[0189] Accordingly, the primed or unprimed substrates commonly employedin the abovementioned technological fields, and coated with at least onecoating of the invention, bonded with at least one adhesive film of theinvention, and/or sealed with at least one seal of the invention,combine a particularly advantageous profile of performance propertieswith a particularly long service life, which makes them particularlyattractive from an economic standpoint.

EXAMPLES Preparation Example 1

[0190] The Preparation of a Polyester Polyol

[0191] In a unit suitable for polyester synthesis, 891.2 parts by weightof Pripol® 1013 (commercial dimeric fatty acid), 292.8 parts by weightof 1,6-hexanediol, 360.3 parts by weight of isophthalic acid and 250.7parts by weight of neopentyl glycol, with xylene as entrainer, werereacted until the acid number was <5 mg KOH/g. The xylene wassubsequently removed by distillation and the polyester was allowed toreact further until the acid number was from 3 to 4 mg KOH/g. Thepolyester was cooled to 110° C. and diluted with methyl ethyl ketone toa solids content of 73% by weight (theoretical). The number-averagemolecular weight was 2333 daltons, the mass-average molecular weight4912 daltons.

Preparation Example 2

[0192] The Preparation of a Polyurethane Prepolymer ContainingIsocyanate Groups

[0193] In a unit suitable for reacting isocyanates, 1535.1 parts byweight of the polyester solution as in Preparation Example 1, 160 partsby weight of dimethylolpropionic acid, 16 parts by weight of neopentylglycol and 636 parts by weight of tetramethylxylylidene diisocyanate(TMXDI) were heated to 90° C. The resulting mixture was diluted with413.9 parts by weight of methyl ethyl ketone to a solids content of 70%by weight (theoretical) and left to react until the isocyanate contentwas constant (2.16% by weight, based on the solids of the polyurethaneprepolymer.

Example 1

[0194] The Preparation of an Inventive Polyurethane and of an AqueousDispersion Thereof

[0195] 1498 parts by weight of the solution of the isocyanato-containingpolyurethane prepolymer from Preparation Example 1 were introduced intothe unit at 90° C. 32.3 parts by weight of thiodiethanol were meteredinto this initial charge with stirring. The resulting mixture wasstirred at 90° C. until isocyanate groups were no longer detectable. Thesolution of the polyurethane of the invention (theoretical solidscontent: 73.9% by weight) was neutralized with triethylamine at 82° C.

[0196] The neutralized solution was dispersed in 1686.5 parts by weightof water to give a dispersion with a solids content of 27.3% by weight.

Example 2

[0197] The Preparation of the Primary Dispersion of an Inventive PolymerMixture

[0198] A customary and known polymerization vessel equipped withstirrer, reflux condenser and two feed vessels was charged with 2674.5parts by weight of the dispersion from Example 1, which was heated to82° C. Metered into this initial charge over 4 hours via the first feedvessel was a monomer mixture comprising 243 parts by weight ofhydroxypropyl methacrylate, 70 parts by weight of n-butyl acrylate, 139parts by weight of styrene, 139 parts by weight of tert-butylcyclohexylacrylate and 104 parts by weight of methyl methacrylate, and 35 parts byweight of tert-butyl per-2-ethylhexanoate were metered in over thecourse of 4.5 hours via the second feed vessel, and the components werecopolymerized at 82° C. Monomer feed and initiator feed were commencedsimultaneously. After the end of the initiator feed, polymerization wascontinued for 1 hour. The resulting primary dispersion (theoreticalsolids content: 46.7% by weight) was diluted with 652.5 parts by weightof water. Its solids content (1 hour/130° C.) was 34.8% by weight, itsacid number 23.1 mg KOH/g and its pH 7.1. The coagulum content was 0.06%by weight. The number average molecular weight of the graft copolymer ofthe invention was 8569 daltons, the mass average molecular weight200,560 daltons.

[0199] The dispersion was poured onto glass, and after drying andphysical curing gave glass-clear coatings. Furthermore, it wasoutstandingly suitable for the preparation of aqueous basecoat materialsor of adhesives and sealing compounds.

1. A polyurethane containing sulfide groups which comprises at least one group of the general formula I in the polymer main chain and/or at least one group of the general formula II incorporated at the chain end: —X—A—S—B—Y—  (I)—x—a—s—b—YH  (II) in which the variables have the following definitions: S is the sulfur atom; X and Y independently of one another are oxygen atoms, sulfur atoms or groups —NZ where Z is the hydrogen atom or an alkyl radical of 1 to 10 carbon atoms; and A and B independently of one another are divalent organic radicals.
 2. The polyurethane as claimed in claim 1, characterized in that said alkyl radicals Z comprise methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl and/or decyl.
 3. The polyurethane as claimed in claim 1 or 2, characterized in that X or Y are oxygen atoms.
 4. The polyurethane as claimed in claim 1 or 2, wherein X and Y are oxygen atoms.
 5. The polyurethane as claimed in any of claims 1 to 4, characterized in that said divalent organic radicals A and B comprise identical or different, substituted or unsubstituted aliphatic, cycloaliphatic, aromatic, aliphatic-cycloaliphatic, aliphatic-aromatic and/or cycloaliphatic-aromatic divalent radicals.
 6. The polyurethane as claimed in any of claims 1 to 5, characterized in that it comprises at least one group of the general formula I in the polymer main chain or at least one group of the general formula I in the polymer main chain and at least one group of the general formula II incorporated at the chain end.
 7. The polyurethane as claimed in any of claims 1 to 6, characterized in that it is preparable by reacting at least one compound of the general formula III: HX—A—S—B—YH  (III) in which the variables have the following definitions: S is the sulfur atom; H is hydrogen atoms; X and Y independently of one another are oxygen atoms, sulfur atoms or groups —NZ where Z is the hydrogen atom or an alkyl radical of 1 to 10 carbon atoms; and A and B independently of one another are divalent organic radicals; with at least one isocyanato-containing polyurethane prepolymer.
 8. A polymer mixture based on polyurethane, preparable by polymerizing at least one olefinically unsaturated monomer with at least one polyurethane containing sulfide groups, as claimed in any of claims 1 to 7, in solution or in an aqueous dispersion.
 9. The use of a polyurethane containing sulfide groups as claimed in any of claims 1 to 7 or of a polymer mixture based on polyurethane as claimed in claim 8, or of a solution or aqueous dispersion thereof as a coating material, adhesive or sealing compound or to prepare a coating material, adhesive or sealing compound.
 10. The use as claimed in claim 10, characterized in that said coating material, adhesive or sealing compound is curable physically, thermally, or thermally and with actinic radiation.
 11. The use as claimed in claim 9 or 10, characterized in that the coating material, adhesive or sealing compound is used in automotive OEM finishing and refinishing, in the coating of interior and exterior architecture, for the coating of furniture, windows or doors and for industrial coating, including coil coating, container coating, and the impregnation or coating of electrical components. 